Re: commit drm/i915: disable shared panel fitter for pipe breaks resolution switching

[Daniel Vetter <daniel@ffwll.ch>]

On Sun, Mar 10, 2013 at 06:02:32PM +0100, Hans de Bruin wrote:
> On 03/06/2013 11:37 PM, Daniel Vetter wrote:
> >On Wed, Mar 6, 2013 at 7:39 PM, Hans de Bruin <jmdebruin@xmsnet.nl> wrote:
> >>On 03/06/2013 03:00 PM, Daniel Vetter wrote:
> >>>
> >>>Hi Hans,
> >>>
> >>>Can you please test with 3.9-rc1? That contains an additional patch
> >>>which might prevent the regression. Specifically
> >>>
> >>>commit 9d6d9f19e8146fa24903cb561e204a22232740e3
> >>>Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
> >>>Date:   Fri Feb 8 16:35:38 2013 +0200
> >>>
> >>>      drm/i915: clean up panel fitter handling in lvds
> >>
> >>
> >>Today's kernel still contains the bug.
> >
> >Hm, I've just retested latest drm-intel-nightly which should have the
> >same set of relevant patches, and I couldn't reproduce your issue.
> >Low-res modes on the lvds panel seem to correctly scale up here on my
> >945gm.
> >
> >Can you pls retest with latest -nightly from
> >http://cgit.freedesktop.org/~danvet/drm-intel ?
> >
> >Also please attach the output of xrandr --verbose when running with a
> >reduced mode.
> >
> 
> tested:
> http://cgit.freedesktop.org/~danvet/drm-intel
> commit d08a6eb2690b1ac6f0582feb41c2ccbea945285f
> Date:   Thu Mar 7 22:54:25 2013 +0100
> 
> The problem is still there
> 
> 
> my previous post contained  the  xrandr output whiteout the verbose.
> Doe you want my to repost with the verbose option?

Sorry for the long delay in taking again a look at this. I've tried to
reproduce this on my various machines similar to yours, but totally
failed. Also, a bunch of people with matching machines to yours actually
claim that the 2 commits which regress for you actually fix up lvds panel
fiting for them. So I'm a bit lost as to what's going on here.

Can you please try the below debug patch on top of latest 3.9-rc kernels?

Please boot that kernel with drm.debug=0xe added to your kernel cmdline,
reproduce the issue (preferrably with xrandr --output LVDS --mode ...) and
then attach the complete dmesg. This will enable lots of debugging, so
please make sure you grab everything starting from when i915.ko loads.

Thanks, Daniel

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index ca2d903..7b2122f 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -155,6 +155,12 @@ static void intel_pre_enable_lvds(struct intel_encoder *encoder)
 	struct drm_device *dev = encoder->base.dev;
 	struct intel_lvds_encoder *enc = to_lvds_encoder(&encoder->base);
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t tmp = I915_READ(PFIT_CONTROL);
+
+	WARN(tmp, "pfit control is dirty: 0x%08x\n", tmp);
+	assert_pipe_disabled(dev_priv,
+			     INTEL_INFO(dev)->gen < 4 || (tmp & PFIT_PIPE_MASK) ?
+			     PIPE_B : PIPE_A);
 
 	if (HAS_PCH_SPLIT(dev) || !enc->pfit_control)
 		return;
@@ -171,6 +177,10 @@ static void intel_pre_enable_lvds(struct intel_encoder *encoder)
 
 	I915_WRITE(PFIT_PGM_RATIOS, enc->pfit_pgm_ratios);
 	I915_WRITE(PFIT_CONTROL, enc->pfit_control);
+
+	DRM_DEBUG_KMS("panel-fitter state: %x, %x\n",
+		      I915_READ(PFIT_CONTROL),
+		      I915_READ(PFIT_PGM_RATIOS));
 }
 
 /**
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch